200W MOSFET CFA amp

[Krisfr]

What are the power supply requirements of a single channel of this amp? va, voltage, caps etc.?

I am relaying out the board for single sided, so I can make it in house, I can not find a inexpensive board maker...as in cheap...

If there are any changes, updates, improvements etc. to the schmo please let me know today.

I only have 4 pairs of FET outputs so that is limiting my thoughts...

I should have ALL other parts in by today.

Breadboarding is an option, but I am not to keen on it.

 

[dadod]

What are the power supply requirements of a single channel of this amp? va, voltage, caps etc.?

I am relaying out the board for single sided, so I can make it in house, I can not find a inexpensive board maker...as in cheap...

If there are any changes, updates, improvements etc. to the schmo please let me know today.

I only have 4 pairs of FET outputs so that is limiting my thoughts...

I should have ALL other parts in by today.

Breadboarding is an option, but I am not to keen on it.

You will need a transformer of 600 VA or more and secondary winding with 2x48 V(up to 2x50 V).
I would suggest the schematic and layout.

 

[mcd99]

Dadod,

Are C6, C7 and snubbers strictly necessary?
Wouldn't the gain of the films be lost by the time you take into account the leads to the amp PCBs?

Paul

 

[dadod]

Dadod,

Are C6, C7 and snubbers strictly necessary?
Wouldn't the gain of the films be lost by the time you take into account the leads to the amp PCBs?

Paul

They are not snubbers, and not strictly necessary. C1, R1 is a snubber.

corrected:
Sorry, I mean those snubbers are not strictly necessary, this is something that could be argued infinitely.
Cordell uses film capacitors parallel to the big elcos in his book, figure 16.8.

 

[AndrewT]

C6, C7, C10 & C11 are not required, or they are in the wrong place.

 

[mcd99]

They are not snubbers, and not strictly necessary. C1, R1 is a snubber.

I thought the items I called "snubbers" were used to damp psu resonances caused by paralleling electrolytics and films?

 

[AndrewT]

No,
the resistor in series with C1, C8 and C9 are the snubbers.
They are there to damp oscillation.
R4 and R5 are only needed because the local decoupling has been moved from the amplifier to the PSU. C6, 7, 10 & 11 are likely to increase the risk of oscillation/ringing.

 

[dadod]

I thought the items I called "snubbers" were used to damp psu resonances caused by paralleling electrolytics and films?

Yes you are correct, I did not notice that you talked about caps and snubbers, and I don't want to start long discussion about it here.

 

[mcd99]

Yes you are correct, I did not notice that you talked about caps and snubbers, and I don't want to start long discussion about it here.

Fair enough...

Edit: Still looking forward to hearing about the first build of this amp.

 

[dadod]

No,
the resistor in series with C1, C8 and C9 are the snubbers.
They are there to damp oscillation.
R4 and R5 are only needed because the local decoupling has been moved from the amplifier to the PSU. C6, 7, 10 & 11 are likely to increase the risk of oscillation/ringing.

Andrew it looks as you did not catch meaning of C10 and C11. They are cross connected between +- polarities to improve +- tracking. The C10 and C11 are in series (it is not easy to find 500u cap with 200 V rating) and parallel resistors are here to devide the voltage. The midle point is not connected to the ground.

 

[Krisfr]

So to be sure, I need (2) two 50 volt sec. at lets say 300 VA each for a 200watt 8 ohm 400watt 4ohm mono block... correct?

2 of these...Antek - AN-6225

 

[dadod]

So to be sure, I need (2) two 50 volt sec. at lets say 300 VA each for a 200watt 8 ohm 400watt 4ohm mono block... correct?

2 of these...Antek - AN-6225

300 VA is not enough, you need 600 VA for 200/400 W mono block.

 

[Krisfr]

Yes the 6225 is 600 VA each

 

[dadod]

Yes the 6225 is 600 VA each

I think 6225 is 2x25 V not 2x50 V.

 

[Krisfr]

I think 6225 is 2x25 V not 2x50 V.

Yes 50 volts for the Plus Rail and the same for the minus. I am going to use one transformer for each rail. For a dual mono block.

 

[dadod]

Yes 50 volts for the Plus Rail and the same for the minus. I am going to use one transformer for each rail. For a dual mono block.

I don't understand, are you going to use two transformers for mono block.
If you use 600 VA transformer use two outputs with 50 V per mono block.

 

[Krisfr]

I am going to use ONE transformer for the PLUS rail and ONE for the Minus Rail...

 

[mcd99]

So for mono you will have two txs and for stereo you will have four?

 

[Krisfr]

So for mono you will have two txs and for stereo you will have four?

Yes Yes and I am going to put the front end on a separate supply too.

 

[mcd99]

Yes Yes and I am going to put the front end on a separate supply too.

DIY Audio at its best.